Add an option to force drag-and-drop under REAPER

This works around a long standing bug in REAPER itself that would
prevent you from dragging files onto any plugin editor window.

src/common/configuration.cpp

@@ -90,6 +90,12 @@ Configuration::Configuration(const fs::path& config_path,
                 } else {
                     invalid_options.push_back(key);
                 }
+            } else if (key == "editor_force_dnd") {
+                if (const auto parsed_value = value.as_boolean()) {
+                    editor_force_dnd = parsed_value->get();
+                } else {
+                    invalid_options.push_back(key);
+                }
             } else if (key == "editor_xembed") {
                 if (const auto parsed_value = value.as_boolean()) {
                     editor_xembed = parsed_value->get();

src/common/configuration.h

@@ -102,6 +102,15 @@ class Configuration {
      */
     bool editor_double_embed = false;
 
+    /**
+     * If set to `true`, we'll remove the `XdndAware` property all ancestor
+     * windows in `editor.cpp`. This is needed for REAPER as REAPER implements
+     * (but doesn't use) drag-and-drop support on all of its windows. This
+     * causes the FX window to intercept the drop thus making it impossible to
+     * drag files onto plugin editors, native or otherwise.
+     */
+    bool editor_force_dnd = false;
+
     /**
      * Use XEmbed instead of yabridge's normal editor embedding method. Wine's
      * XEmbed support is not very polished yet and tends to lead to rendering
@@ -173,6 +182,7 @@ class Configuration {
     void serialize(S& s) {
         s.value1b(cache_time_info);
         s.value1b(editor_double_embed);
+        s.value1b(editor_force_dnd);
         s.value1b(editor_xembed);
         s.ext(frame_rate, bitsery::ext::StdOptional(),
               [](S& s, auto& v) { s.value4b(v); });